Metabolism

Metabolism

The total of all chemical reactions occurring within a cell to maintain life.

Catabolism

The metabolic pathway that breaks down molecules into smaller units and releases energy.

Anabolism

The metabolic pathway that builds complex molecules from simpler ones, consuming energy.

Relationship between catabolism and anabolism

Catabolism releases energy that can be used to power anabolic reactions.

Energy

The capacity to do work or cause change.

Kinetic Energy

The energy of motion, such as moving molecules.

Potential Energy

Stored energy due to an object's position or structure.

Chemical Energy

Potential energy stored in chemical bonds of molecules.

First Law of Thermodynamics

Energy cannot be created or destroyed, only transformed.

Second Law of Thermodynamics

Every energy transfer increases the entropy (disorder) of the universe.

Free Energy (Gibbs Free Energy)

The energy available to do work in a system at constant temperature and pressure.

Exergonic Reaction

A reaction that releases free energy and occurs spontaneously.

Endergonic Reaction

A reaction that requires an input of energy and is not spontaneous.

ATP

Adenosine triphosphate; it stores and transfers energy for cellular processes.

How ATP releases energy

By breaking the bond between its second and third phosphate groups (hydrolysis).

Phosphorylation

The addition of a phosphate group to a molecule, often to activate it.

Role of Enzymes in Metabolism

They speed up metabolic reactions by lowering the activation energy.

Activation Energy

The minimum energy required for a chemical reaction to occur.

Environmental Factors affecting Enzyme Activity

Temperature, pH, and the presence of inhibitors or activators.

Why is Metabolism Tightly Regulated?

To ensure cells have enough energy, maintain balance, and respond to changes in the environment.